About Breast Cancer

Are there stem cell therapies available for breast cancer?

To our knowledge, no stem cell therapy has received Health Canada or U.S. Food and Drug Administration approval for the treatment of breast cancer at this time. Patients who are researching their options may come across companies with Web sites or materials that say otherwise and offer fee-based stem cell treatments for curing this disease. Many of these claims are not supported by sound scientific evidence and patients considering these therapies are encouraged to review some of the links below before making crucial decisions about their treatment plan. However, the field of breast cancer research is fast-moving and work underway today may uncover new possibilities for more effective treatments tomorrow. Therefore, it is important to keep asking questions and continue seeking advice from qualified experts.

For the latest developments read our blog entries here.

For more about stem cell clinical trials for breast cancer click here.  (For printed version: http://goo.gl/ubLRo)

How close are we? What do we know about breast cancer?

  • All breast cancers develop first as local “solid” tumours from cells in the mammary gland. Some appear abruptly, but most grow slowly and, unless observed early by chance, may remain undetected until they are well established.
  • The development of a breast cancer is a multi-step process that involves an accumulation of many errors (mutations) in normal breast cells. Eventually this may lead to an early stage breast cancer where the cells have begun to grow out of control but cannot yet leave the mammary gland.
  • Advanced breast cancers have already spread to the draining lymph nodes and the rest of the body, most often to the bone, liver, and lungs where satellite tumours (called metastases) begin to grow.

How can knowledge of stem cells play a part in breast cancer?

Knowledge acquisition is the key to making progress in the field of breast cancer, where a major research focus is on asking basic questions about cancer cells and how breast cancer stem cells differ from their normal counterparts. Building on the cancer stem cell hypothesis – the idea that cancer is propagated by a small subset of cells with stem cell properties – has been extremely important because this hypothesis implies that cancer stem cells must be eliminated to achieve a cure. But identifying and studying cancer stem cells is a challenge because they are often rare elements in the tumour. Two recent breakthroughs are making a big difference in addressing this challenge. One is the development of mice that can live without any immune system and the discovery that transplants of human breast tumours can grow efficiently in these mice so that they can be used as model patients to test which cells make the tumours grow and how to kill them. The second breakthrough has been the discovery of specific molecules (called biomarkers) on tumour cells. Biomarkers have been critical in identifying and isolating breast cancer stem cells from other cells in the tumour. This kind of research is opening the door to identifying breast cancer earlier, predicting its prognosis, diagnosing particularly aggressive forms of the disease, and providing possible targets for drug therapy.

Are there lots of groups working to develop therapies targeting breast cancer stem cells?

There are numerous research teams around the globe working to evaluate the importance of cancers stem cells in designing more effective treatments for breast cancer.

One of the most important research contributions to date has come from Canadian scientist John Dick. In 1994, his team at the University of Toronto and The Hospital for Sick Children identified a small population of tumour initiating cells that could generate human leukemia in transplanted mice. This discovery paved the way for the identification of cancer stem cells in other solid tumours found throughout the body, including in breast (2003), brain (2004) prostate (2005) and colon (2006).

The application of stem cell research to breast cancer is moving along a number of different routes, some of which are being translated into very early clinical trials. These studies involve using new methods to monitor the cells and DNA present in patients by assessing tissue samples before surgery, at the time of removing the cancer, and for many years afterwards. Other studies are testing whether cancer stem cell biomarkers can be used to predict responses to therapies for early stage breast cancer. Researchers hope that these types of studies will help them to identify cancer stem cells in tumours and/or normal tissue, predict the likelihood of recurrence sooner than by current methods, and correlate changes in breast cancer stem cells with responses to therapies.

What research is underway?

As a pre-requisite to developing therapies targeted at cancer stem cells, many questions must first be answered. What gives a cancer cell “stem cell” properties? And what distinguishes cancer stem cells from normal stem cells of the same tissue? What molecules and pathways inside the cell can keep cancer stem cells quiet (non-dividing) but still alive and which ones unleash uncontrolled growth? And how does a cancer stem cell genome affect the type of tumour that grows? Pursuing these answers has required innovative strategies from researchers to develop novel methods for isolating and characterizing cancer stem cells. The field has benefited from the technological refinements in separating different subsets of cells without killing them so that they can be tested for their ability to generate tumours in immunodeficient mice. Another important area has been the development and application of methods to identify rapidly and in exquisite detail every mutation that is present in a population of tumour cells and, similarly, to be able to measure the level of every gene that is active.

The road to finding therapies targeting breast cancer stem cells is paved with many challenges that will take time to overcome. But the wealth of information about breast cancer stem cells generated from labs around the globe is converging to help with the transition from basic research to the clinic. The foundation of studies on human breast cancer stem cells has been greatly advanced by the creation of methods to characterize the normal counterparts in the breast. Landmark studies have recently described the changing genomic composition of a single breast cancer over time, the architecture of mutations of thousands of breast tumours and the changing spectrum of tumours in triple negative breast cancer. All in all, this research provides the most advanced data on breast cancer, not only identifying new subgroups within breast cancer but also underscoring the molecular individuality within breast cancer populations. Being able to categorize breast cancers in this way creates a better picture of the disease and provides a new context for understanding why responses to therapies can vary so greatly.

Further reading on breast cancer

Readers may wish to peruse the recommended sites and articles below for more information about breast cancer stem cells and how understanding them better may lead to new therapies to treat breast cancer.

American Cancer Society (www.cancer.org)
BC Cancer Agency (www.bccancer.bc.ca)
Canadian Cancer Society (www.cancer.ca)
Cancer Research UK (http://goo.gl/qs7Ne)
National Cancer Institute (U.S.) (www.cancer.gov/cancertopics/types/breast)